The cIass of IInear alternating polymers of carbon monoxide and ethylenically unsaturated compound is known in the art. An early production of such polymers is disclosed by a number of U.S. patents to Nozaki oi which U.S. Pat. No. 3,694,412 is illustrative. More recently, processes for the production of linear alternating polymers are shown by a number of published European Patent Applications including 121,965, 181,014, 213,671 and 257,663. Many, if not most, of the available processes are directed to the produciion of linear alternating polymers of carbon monoxide and acyclic ethylenically unsaturated hydrocarbons but the scope of the polymerization process is not so limited. Somewhat special considerations do apply for the polymerization of compounds that are cyclic and/or nonhydrocarbon.
A copending U.S. patent application, Ser. No. 379,839, filed July 14, 1989, is directed to the production of linear alternating polymers of carbon monoxide and cyclic compounds illustrated by 5-norbornene-2,3-dicarboxylic acid anhydride. The reactants are contacted in methanol as a reaction diluent and a lower olefin such as ethylene must be present. Even in the presence of ethyIene the polymer product is a copolymer derived from carbon monoxide and 5-norbornene-2,3-dicarboxylic acid anhydride and terpolymer products are not observed. Because of the presence of reactive acid anhydride groups and the methanol reaction diluent, a portion of the norbornene-type monomeric units are observed in the form of methyl esters.
One possible application for linear alternating polymers broadly would be as pour point depressants for paraffin-based motor oils if the polymers contained long-chain alkyl groups depending from the polymer chain. However, direct polymerization of carbon monoxide and higher olefinic hydrocarbons, e.g., an a-olefin of 8 or more carbon atoms, leads to products which are not entirely satisfactory ior this purpose. It would be of advantage to provide other linear alternating polymers, both copolymers and terpo-ymers, which contain long chain alkyl groups as pendant substituents of the polymer chain.